> Instead of learning the lingua franca and being able to verify your own work, "the rest of the team" has to make sure your PR's will not obviously fail.

I lead the engineering team at my org and we hire almost exclusively for c++ engineers (we make games). Our build system by happenstance is written in c#, as are all the automation scripts. Out of our control to change. Should we require every engineer to be competent and write fluent c# or should we let them just get on with their value adds?

Programming language are not actually that different. There’s only a few models of computation and paradigms. The effort is mostly about learning the syntax, the standard library and whatever abstractions built around the above paradigms and computation models. And learning the standard library is the tough one.

I would expect every engineer to be able to read C#. It’s not that hard.